Process and apparatus for dehydrating tissue prior to embedding in paraffin and the like



g- 7, 1951 J. TANNENBERG 2,562,956

PROCESS AND APPARATUS FOR DEHYDRATING TISSUE PRIOR TO EMBEDDING IN PARAFFIN AND THE LIKE Filed May 11, 1948 tissue to be Patented Aug. 7, 1951 ING TISSUE PRIOR TO EMBEDDING IN PARAFFIN AND THE LIKE Joseph Tannenberg, caravan. Y. Application May 11, 1948, Serial No. 26,444

This invention relates to a process and. ap..

paratus for dehydrating pieces or specimens of 7 used for histological purposes,

microscopic examinations, etc.

It is one of. the advantages of this invention to provide means ensuring automatic and substantially continuous flow, or. cycle of dehydrating fluid through a plurality of tissue specimens and like objects to be treated.

It is another advantage of the invention to provide means facilitating automatic change and replacement of the dehydrating fluid within.

an apparatus in which the aforesaid tissue pieces are placed for treatment.

Still a further advantage of this invention is to provide means for speedily and safely dehydrating tissue specimens and like substances without moving or contacting the same, for instance, by an operator during the entire dehydrating process.

Yet another object of this invention resides in the provision of means preventingany accidental drying out of the tissue samples under treatment in the event that continuous fiow of dehydrating, fluid should be interrupted.

Still another object of the invention istoprovide means afiording re-use of the dehydrating fluid by freeing it from water or watery admix tures which it has absorbed during preceding dehydrating processes.

These and other objects of the invention will be pointed out in the following description and claims and illustrated in the accompanying drawing which discloses, by way of example, the principle of the invention and preferred modes which have been contemplated for applying said principle. I v

In the accompanying drawing the process and apparatus made in accordance with this invention is schematically illustrated. It is well understood that the embodiment shown is one ofv l5 for connection with a tube I6 leading into an inlet in the upper part of container or receptacle H which is tightly closeable by a lid I8 having a handle 19.. Withinthe container orreceptacle I! there are arranged a plurality of.

. lengthy trays 29, 2|, 22 which are filled with layers23 of calcium chloride, calciiun oxide or,

like chemicals. On top of trays 20, 2!, 22 are placed a plurality of embedding containers or.

boxes with openings or perforations 24 similar in construction to those described in my Patent No. 2,437,713, dated March 16, 1948 and through a which communication between boxes 25 and;

trays 2%), 2%, '22 within container I'I takes place.

Within the compartments 26 of each embedding apparatus or box 25 are placed tissue pieces 21 to be dehydrated.

Connected to receptacle ll and at a level of the tissue samples deposited on the bottom of the embeddin boxes 25 (only one embedding box being shown-for clarity s sake) is the outlet of knee-shaped tube 28 having an upwardly turned bend 29 and a downwardly extending leg 39, the'latter leading into the lower part of a is completely water-free and will now flow out through conduit into the collecting tank that may be made completely interchangeable withtank ll). This collector tank M] is constructed similar to tank i6 and has the upper opening 3'! .into which tube 35 leads and has the valve 38 with fitting or connection 39 near the bottom of tank 46.

It will be easily realized that provisions may be made for use of tank 46 to replace tank ll) when the latter is emptied and tank 40 is refilled with clean dehydrating fluid for re-use.

The apparatus or plant 50 is constructed to automatically dehydrate a plurality of tissue or drated from one container to another filled with dehydrating fluid of increasing concentration is avoided but the dehydrating fluid instead is con tinuously and automatically renewed within the same container in which the tissues have been placed until complete dehydration has been rq is When the.

Aside from the relatively slow continuous change of the fluid, several abrupt and total changes of the fluid surrounding the tissue samples to be dehydrated are also provided in this apparatus by employing the syphon principle on account of which the embedding apparatuses or boxes containing the tissue samples to be dehydrated are" automatically emptied and" refilledwith fresh dehydrating fluid.

The manner in which the plant 50 hereinabove outlined is operated will now be further ex'-' plained. The tissues 2'! to be dehydrated are placed in the compartments '26 of the-respective boxes or containers 25 which are arranged next to each other on top of the trays 20, 2|, 22, which extend in perpendicular direction to the embedding boxes 25. stood that receptacle I! may be made of any desired size and dimensions in order to accom modate therein a plurality of boxes 25. Valve I' l.- is. then opened in such manner: that dehydrating fluid; such" as dioxane, is discharged in a contin'uous' and-slow flow from tank It] through the pipel6 into receptacle l1 untilzan' upper filling level corresponding. to bend 29'is reached in the receptacle.

Thereafter a syphoning or suction effect is produced in inverted U-shaped conduit 28-29- 3'fl whereby thatpart of the dehydrating fluid l'la' which has absorbed water from the tissue" pieces tobe dehydrated and which assumes a level above theoutlet of conduit 36 and below inlet of tube IS in receptacle IT is then forced-'- into the purifying tank 3!. The dehydrating fluid l lahas already been cleaned upon contact with-water absorbing chemicals-23, such as cal-- cium chloride, calcium oxideor the like" placedin=trays 20,- 2], 22'. The dehydrating fluid Ila upon: reaching within receptacle IT a level'corresponding to the bend 2 9 ofconduit 30 is-then subjected to the-syphoning effect produced in conduit 30 whereby receptacle I! will be emptied from-said filling level at 29 quite fast'down to approximately somewhat abovethe level'ofthe bottom-of the boxes'Zif-onwhich the tissue pieces rest'.

This syphoning action will be automatically interrupted until such time at which the receptacle'will be supplied with further make-up" fluid and again'filled up through supply tube I 6 whereupon automatically the syphoning-effect is eflectua'ted again in a manner heretofore described.

This step automatically repeats itself until tank lllhas been emptied. If tank I0 is made of a size: to'contain about two gallons. of dehydrating" fluid, this will be enough to automatically com-' plete dehydration of about to 'tissue samples placed in receptacle i'i within-a relatively short period of time. A

Thedehydrating fluid entering tank 31 isnow further freed'fi'om' water or watery admixtures upon contact with calcium chloride or the like placed on the bottom of tank 3|. Assoon as' level 34 of dehydrating fluid breaches the heightof t'ube35' the entirely purified dehydrat ing'fluid'will be conducted to thecollector tank 40*forre-use as it'is'well understood;

It can be easily realized that conta'iner's'o'r tank's IO, Ii; SIQand 40 should be fitted with tightly; closing'lids to prevent evaporation ofth'e' dehydrating-fluid: These" tanks-are further so arranged that 'tliedehyd ratin'g fluid may be sup pliedfro'nr tank Illb'y gravity-and the" contain-' are [0, l1, 3|, and 40 are so arranged witli're It is, of course, under- 4 spect to each other that the aforesaid syphoning' effect may be brought about in a most effective manner.

In this connection it is to be mentioned that outlet 28 of conduit 30 is so arranged with respect to the bottom of the embedding or dehydrating boxes 25 that the tissue samples therein' will always remain incontact with the dehydrating fluid and willthus be prevented from drying out within their compartments in the event that the continuous flow or supply of the dehydrating fluid into tank or receptacle I! is interrupted;

It isafurther understood that any other known waterabsorbent chemicals can be employed to purifythe' dehydrating fluid used, provided that these chemicalshave a greater affinity for Water than the dehydrating fluid employed has.

The principle of this hereinabove described process is to accelerate and to economically bring aboutdehydrationof a plurality of tissue samples simultaneouslyto be embedded for histiological purposes'by' effectuating constantly and automatically changing flow of dehydrating-fluid.

It can thus be seen'that there has been-provided inaccordance' with the present invention a process of automatically dehydrating. tissue This consists in subjecting tissue sam samples. ples to the continuous change of dehydrating fluid,.permitting.said fluid to contact said tissue for a predetermined length of time, and thereafter causing a syphoning. effect on said dehydi'ating fluid to thereby forcedly and automatically bring about complete dehydration to said. tissue samples.

It might be desirable'to provide tanks l0 and dci with aglass gauge which permits the easy reading. of the level of the fluid within each tank;

As many possible embodiments may be con-- ceived of the above invention; and as alterationsand --changes may be made in the embodi-- ments albove set forth, it is to be stated that all mattershereinbefore explained or shown in the accompanying-drawing, are to be interpreted ab'ove said tissue pieces while said fluid remains in contact with-said-tissuepieces,- whereby saidtissue-piecesare automatically dehydrated without being exposed to desiccation, and feeding further fluid tosaidtissue-pieces' while fluid is syp'honedoff.

2 An apparatus' for dehydrating tissue and like articles for histiological purposes comprising a first tankfrom which dehydrating liquid is supplied, a-receptacle including a' perforated containerhaving a" bottom fonholding said tissue :articles to be-treate'd; a second tank-for collectingsaid dehydrating liquid, said receptacle b'eing positioned intermediate-said first tank and said. second ta nkandbeing cennectedwith said tanks by respectivecond'uits,- theconduit extending betwee saidreceptacle-a-nd said second tank including" an inverted U-shaped tube having anoutletfrom said receptacle at a'level abovethe bottom of P said 1 container, the bend of said" in-' verted' U-shaped tube being-positioned above sa'id outletto attainasyphoning efiect between said receptacle and said second tank, as soon as said dehydrating liquid reaches a predetermined level in said receptacle.

3. An apparatus according to claim 2, wherein said conduit connecting said first tank with said receptacle terminating in an inlet within said receptacle, said bend bein positioned intermediate said inlet and said outlet, said bottom of said container being arranged at a level below said inlet said outlet and said bend.

4. The process of simultaneously dehydrating a plurality of pieces of tissue and like articles comprising the steps of first placing said tissue pieces in a perforated container within a receptacle, introducing into said receptacle dehydrat ing fluid for contact with said tissue pieces, causing said fluid to reach a predetermined level in said receptacle at which said contact with said tissue pieces is maintained at all times, thereafter withdrawing fluid from said receptacle through syphoning means which is connected to said receptacle at said predetermined level and extends thereabove relatively to the top of said receptacle to thereby obtain a filling level of said fluid within said receptacle, and continuously feeding makeup fluid into said receptacle upon syphoning off fluid above said predetermined level, whereby said tissue pieces are continuously and automatically dehydrated without being exposed to desiccation.

5. The process of continuously dehydrating pieces of tissue and like articles comprising placing said tissue pieces in a receptacle, then introducing into said receptacle dehydrating fluid for contact with said tissue pieces, causing said fluid to assume a predetermined level in said receptacle to thereby maintain contact of said fluid with said tissue pieces, syphoning off fluid above said predetermined level to thereby adjust an upper filling level for said receptacle, and continuously feeding make-up fluid into said receptacle up to said filling level whereby said tissue pieces are continuously and automatically dehydrated without being exposed to desiccation.

6. The process of dehydrating pieces of tissue and like articles which consists in subjecting said tissue pieces to the influence of dehydrating fluid within a receptacle through which said fluid passes, causing said fluid to maintain within said receptacle a predetermined level to thereby establish continuous contact with said tissue pieces, syphoning ofl fluid above said predetermined level to thereby adjust an upper filling level for said receptacle, and continuously feeding make-up fluid into said receptacle up to said filling level, whereby said tissue pieces are continuously and automatically dehydrated without being exposed to desiccation.

7. The process of simultaneously and automatically dehydrating a plurality of tissue pieces or like articles; comprising the steps of placing said tissue pieces in perforated means, thereafter placing said perforated means with said tissue pieces in a receptacle, introducing and partly filling said receptacle with dehydrating fluid to thereby assume a predetermined low fluid level, at which said tissue pieces within their perforated means are covered by said fluid, regulating supply of make-up dehydrating fluid to said receptacle to fill same in such a manner that said fluid will rise slowly within the receptacle from said predetermined low level to a predetermined upper level therewithin whereby floating out of said tissue pieces from said perforated means to the surface of the rising dehydrating fluid is prevented, interrupting automatically further rise of said continuously supplied make-up fluid as soon as said fluid reaches said predetermined upper level by comparatively fast removing fluid through U-shaped bent syphoning means connected to said receptacle at said low fluid level and having the bend at said upper level, whereby said syphoning means removes fluid from the receptacle at a faster rate than the rate of make-up fluid supply to thereby permit automatic interruption of the removal of dehydrating fluid from the aforementioned receptacle when the fluid has reached said predetermined low level, purifying and freeing said dehydrating fluid thus syphoned off from water by dehydrating means, and reusing the resultant purified dehydrating fluid for supply of make-up fluid into said receptacle.

8. The process of simultaneously and automatically dehydrating a plurality of tissue pieces or like articles; comprising the steps of placing said tissue pieces in a receptacle, introducing into said receptacle dehydrating fluid to thereby fill same to a predetermined low fluid level, at which said tissue pieces are covered by said fluid, regulating supply of make-up dehydrating fluid to said receptacle to fill same from said predetermined low level to a predetermined upper level therewithin, and causing automatic interruption of further rise of said make-up fluid in said receptacle as soon as said fluid reaches said predetermined upper level by comparatively fast removing fluid through U-shaped bent syphoning means connected to said receptacle at said low fluid level and extending with its bend to said upper level, whereby said syphoning means removes fluid from the receptacle at a faster rate than the rate of make-up fluid supply to thereby permit automatic interruption of the removal of dehydrating fluid from the aforementioned receptacle when the fluid has reached said predetermined low level.

JOSEPH TANNENBERG.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,795,006 Boiney Mar. 3, 1931 2,284,248 Baker et al. May 26, 1942 2,295,912 Pagenkopf Sept. 15, 1942 2,348,631 Keehnel May 9, 1944 

1. THE PROCESS OF DEHYDRATING PIECES OF TISSUE AND LIKE ARTICLES WHICH CONSISTS IN IMMERSING SAID TISSUE PIECES IN DEHYDRATING FLUID LEVEL ING OFF FLUID FROM A PREDETERMINED FLUID LEVEL ABOVE SAID TISSUE PIECES WHILE SAID FLUID REMAINS IN CONTACT WITH SAID TISSUE PIECES, WHEREBY SAID TISSUE PIECES ARE AUTOMATICALLY DEHYDRATED WITHOUT BEING EXPOSED TO DESICCATION, AND FEEDING FURTHER FLUID TO SAID TISSUE PIECES WHILE FLUID IS SYPHONED OFF. 